Control device for robot having arm

1. A control device of a robot having an arm, the control device comprising: a motor that generates torque in each axis of the robot; a torque generation control unit that controls the motor so as to generate a canceling torque which cancels friction of each axis of the robot when controlling the robot by external force tracking; and a torque changing unit that changes the canceling torque to a reference value or less.

2. The control device according to claim 1 , wherein the torque changing unit changes the canceling torque based on a speed feedback value from the motor, or an estimated value of a force applied by a user to the arm.

3. The control device according to claim 2 , wherein, in a case in which the speed feedback value or the estimated value is a first threshold value or less, the torque changing unit changes the canceling torque to a value between zero or more and a second threshold value or less, and in a case in which the speed feedback value or the estimated value is a third threshold value which is greater than the first threshold value or more, the torque changing unit changes the canceling torque to a value between zero or more and a fourth threshold value which is greater than the second threshold value or less.

4. The control device according to claim 2 , wherein, in a case in which a distance between a boundary of an operable area of the arm and a center point of a tip end portion of the arm is a fifth threshold value or less, the torque changing unit changes the canceling torque so that the distance and a gain used for changing the canceling torque have a positive correlation, and sets the gain to zero when the distance is zero.